[comp.sys.ibm.pc.hardware] How compatible are Packard-Bell machines?

tgl@g.gp.cs.cmu.edu (Tom Lane) (10/10/90)

I have a program that expects to drive Hercules-type monochrome
graphics displays.  It pokes the CRT controller at the hardware level,
and also pokes various BIOS RAM locations to keep things consistent.
(I didn't write this sucker, I just hafta support it.)
It works pretty well on the machines I've tried it with, but...

I got a report from a person trying to use this program on a
Packard-Bell machine with a supposedly Hercules-compatible display.
All that he gets is a bright vertical line near the middle of the
display.  This sounds a whole lot like horizontal retrace being lost,
but it's tough to tell at long distance.

Does anybody know if Packard-Bell displays really are compatible
at the hardware level with Hercules boards?  How about their BIOS?
I'm using the 720x348 graphics mode (67 hex), in case it matters.

I'm sure 99% of the net couldn't care less, so please reply by e-mail.

-- 
				tom lane
Internet: tgl@cs.cmu.edu
UUCP: <your favorite internet/arpanet gateway>!cs.cmu.edu!tgl
BITNET: tgl%cs.cmu.edu@cmuccvma
CompuServe: >internet:tgl@cs.cmu.edu